Pat the steak cubes dry with paper towels to ensure even browning.
In a large bowl, combine steak bites with olive oil, garlic powder, onion powder, smoked paprika, salt, black pepper, and cayenne pepper (if using). Toss to coat evenly.
Preheat the air fryer to 400°F (200°C) for 3 minutes.
Place the steak bites in a single layer in the air fryer basket, leaving space between pieces for proper air circulation.
Air fry for 8–10 minutes, shaking the basket halfway through, until steak reaches desired doneness (130°F for medium-rare, 140°F for medium).
Remove steak bites from the air fryer and let rest for 2–3 minutes.
Drizzle with melted butter (optional) and garnish with chopped parsley before serving.
Notes
For best results, do not overcrowd the air fryer basket. If cooking a larger batch, work in batches to ensure even cooking.